From bada.org/object/frances-catherine-legge-nee-nicoll-countess-dartmouth-17323-1805-tilly-kettle-1734-1786. Also posted to the Reign of Louis XV -1715 to 1774 Album here by her 1757 Reynolds portrait in court dress.
The Countess of Dartmouth's dress has all of the lace trimmings - a tucker, bertha, bows en échelle, arm bands, and engageantes.
Keywords: Kettle, Frances Catherine Nicoll, Countess of Dartmouth, Nicoll family, Legge family, Countess, British, straight coiffure, lace-trimmed wire cap, strap, lace-trimmed chemise, modesty pice, trapezoidal neckline, lace tucker, vee neckline, fitted bodice, square neckline, lace bertha, three quarter length close sleeves, lace bows, lace engageantes, bracelets, lace bows en échelle